ldc-volena/app/Traits/Models/Orderable.php

<?php

namespace App\Traits\Models;

use Illuminate\Database\Eloquent\Model;

trait Orderable
{
    /**
     * Returns the grouping field used for ordering.
     * Returns null if the order is global
     *
     * @return string|null
     */
    public function getOrderGroupField(): ?string
    {
        return null;
    }

    /**
     * Set order after the last element of the list.
     *
     * @param Model   $model
     * @param boolean $isDeletion
     * @return void
     */
    public static function setOrder(Model $model, bool $isDeletion = false): void
    {
        /** @phpstan-ignore-next-line */
        $groupField    = $model->getOrderGroupField();
        $maxOrderQuery = $model::query();

        if ($groupField) {
            $maxOrderQuery->where($groupField, $model->{$groupField});
        }

        $maxOrder = \intval($maxOrderQuery->max('order'));

        if ($isDeletion) {
            $query = $model::query()
                ->whereKeyNot($model)
                /** @phpstan-ignore-next-line */
                ->whereBetween('order', [$model->order, $maxOrder]);

            if ($groupField) {
                $query->where($groupField, $model->{$groupField});
            }

            $query->decrement('order', 1);
            return;
        }

        /** @phpstan-ignore-next-line */
        $model->order = $maxOrder + 1;
    }
}